1. Field of Invention
The present invention relates to an external airbag structure of a vehicle, more particularly, to a venting structure for discharging gas of an airbag cushion.
2. Description of Related Art
As desire for an improved safety for a vehicle has increased and has become a high-quality, a concern for an exterior for the vehicle has been high. In particular, it has been proposed that an external airbag is provided at front of a front bumper so that an air bag is developed in advance before a chassis substantially collides with obstacles on a crash. Such an airbag ensures that it makes an absorbing interval of collision energy longer to reduce a collision impact applied to a passenger.
In order to perform an appropriate cushion action of the external airbag cushion as described above, such an airbag cushion should have 5 to 20 times more absorbing energy than the existing airbag cushion disposed at an indoor for protecting a passenger. To accomplishing this, it is necessary that the airbag cushion has 5 to 15 times in an energy absorption, has a about 5 to 15 times size and an inflator have a 10 to 20 times capacity compared with the existing airbag cushion. In this case, gas injected from the inflator has a high temperature that exerts an adverse effect on a person or things around a vehicle based on a discharging direction.
In addition, the inflator has a limited capacity. Therefore, since a vent hole of the airbag of the cushion is initially closed, it is preferable that the airbag cushion is made to develop as quickly as possible and is opened to discharge gas after a completion of the development of the airbag cushion to properly take a cushion effect.
The information disclosed in this Background section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.